KR101462486B1 - Elastic infill for artificial turf - Google Patents

Abstract

In the present invention, provide is an elastic filler for artificial grass which is a pellet made from an elastic composition including a base resin containing an olefin copolymer and an inorganic filler compound containing a silane coupling agent, where the silane coupling agent exists in a type of mixture with the compound or in a type of cross linking by being grafted onto the olefin copolymer.

Description

[0001] Elastic infill for artificial turf [0002]

TECHNICAL FIELD The present invention relates to an elastic filler for artificial turf, and more particularly to an elastic filler for artificial turf having excellent heat resistance.

Artificial turf has the texture of natural grass, can be used for a long time, has a low maintenance cost, and prevents the injury caused by cushion. Artificial turf structure is a kind of artificial turf which is filled with rubber chips and sand to give a carpet-like artificial turf similar texture to natural turf. However, the hazard caused by the waste tire rubber chip used as artificial turf filler is emerging as a social issue. Since the waste tire rubber chip is blackish, it absorbs the sunlight and raises the temperature of the ballpark, which can deteriorate the running environment. In the summer when the temperature exceeds 30 ° C, there is a smell coming from the rubber chip, and the rubber chip melted in the hot geothermal heat may stick to it. Due to the characteristics of the process of producing waste tire chips by pulverization, the pulverized chips may be crushed during long-term use, causing dust to contaminate the surroundings. In Europe, it has been reported that harmful substances such as heavy metals, polynuclear aromatic hydrocarbons, toluene, benzene and nitrosamine have been detected in artificial turf, and the demand for alternative materials to replace waste tires with artificial turf filler is increasing.

According to one aspect of the present invention, there is provided an elastic filler for artificial grass obtained by pelletizing an elastic composition comprising a silane coupling agent in a mixture of a base resin containing an olefin copolymer and an inorganic filler, There is provided an elastic filler for artificial turf which exists in a mixed state or is grafted to the olefin copolymer to form the olefin copolymer in the form of water.

According to another aspect of the present invention, there is provided a method for producing an elastomer composition comprising the steps of: providing an elastomer composition comprising a silane coupling agent to a mixture of a base resin containing an olefin copolymer and an inorganic filler; Kneading the elastomer composition; And a step of extruding and pelletizing the kneaded elastomer composition to obtain an elastic filler. The present invention also provides a method for producing an elastic filler for artificial turf.

 As described above, in the case of a rubber chip made by crosslinking EPDM rubber which is recently used instead of a harmful waste tire chip, it is essential to grind the crosslinked material in order to make it into a chip. There is a problem of scattering and an unnecessary space is generated between the rubber chips due to the irregular surface shape, so that the cohesion force between the rubber chips is dispersed, so that the grass is not properly supported.

Korean Patent Laid-Open Publication No. 10-0799262 discloses an eco-friendly grass filler composition comprising styrene-ethylene-butadiene-styrene (SEBS), olefinic elastomer, mineral oil, inorganic filler, weathering stabilizer and inorganic pigment. In the above document, there is disclosed an advantage that chips are produced by pelletization by extrusion rather than being produced by pulverization, and dust is not generated after application. However, because SEBS resin is more than twice as expensive as general rubber or polyolefin elastomer, It is not economical to use it and there is a limit to expanding the market. When an olefinic elastomer is mixed with SEBS, the material cost is lowered. However, since the melting point of the blended olefin elastomer resin is low, the filler using the filler has insufficient heat resistance and elastic recovery characteristics. The pellets may stick to each other. Therefore, there has been a demand for an improved elastic filler for artificial turf.

Hereinafter, the techniques disclosed in this specification will be described in detail.

According to one embodiment, an elastic filler for artificial turf is a pelletized composition comprising a silane coupling agent in a mixture of a base resin containing an olefin copolymer and an inorganic filler. Wherein the silane coupling agent is present in admixture with the mixture or is grafted to the olefin copolymer so that the olefin copolymer is present in a water-soluble form.

In one embodiment, the olefin copolymer may be an ethylene copolymer. Wherein said ethylene copolymer is selected from the group consisting of i) ethylene, and ii) a C3-C10 alpha monoolefin, a C1-C12 alkyl ester of a C3-C20 monocarboxylic acid, an unsaturated C3-C20 mono- or dicarboxylic acid, an anhydride of an unsaturated C4-C8 dicarboxylic acid, And a vinyl ester of a C2-C18 carboxylic acid.

The ethylene copolymer is a soft polymer having hardness between Shore A 40 and Shore A 95, and is excellent in oxidation resistance and weatherability, excellent in elasticity, and low in cost, thus being the most suitable polymer for the requirements as an elastic filler.

Specific examples of the ethylene copolymer include ethylene vinyl acetate (EVA), ethylene butylacrylate (EBA), ethylene methylacrylate (EMA), ethylene ethyl acrylate, EEA), ethylene methyl methacrylate (EMMA), ethylene butene copolymer (EB-Co), and ethylene octene copolymer (EO-Co).

In one embodiment, the olefin copolymer may be an olefin / alpha-olefin copolymer. The term "olefin / alpha-olefin copolymer" as used herein generally refers to a polymer comprising ethylene or propylene and alpha-olefins having two or more carbon atoms. The? -Olefin is an olefin having 2 or more carbon atoms and having a double bond at the terminal.

Preferably, ethylene or propylene accounts for the major mole fraction of the total polymer, i.e., ethylene or propylene accounts for at least about 50 mole percent of the total polymer. More preferably, the ethylene or propylene occupies at least about 60 mol%, at least about 70 mol%, or at least about 80 mol%, and the substantial remainder of the total polymer is preferably an alpha -olefin having at least three carbon atoms One or more other comonomers. For example, in the case of an ethylene / octene copolymer, the preferred composition comprises an ethylene content of at least about 80 mole percent of the total polymer, and an octene content of from about 10 to about 15 mole percent, preferably from about 15 to about 20 mole percent, .

The olefin /? - olefin copolymer may be a random copolymer or a block copolymer. Examples of OAO are Ethylene Alpha Olefin (EAO) or Propylene Alpha Olefin (PAO), and many products are commercially available. EAO includes Dow Chemical's Engage and Infuse, Mitsui's Tafmer, Exxon Mobile Exact, LG Chem's LG -POE, etc. PAOs include Dow Chemical's Versify, Mitsui's Notio, and Exxon Mobile's Vistamaxx.

In one embodiment, the olefin / alpha-olefin copolymer used in the filler for artificial turf is an olefin block copolymer (OBC). The olefin block copolymer (OBC) is a multi-block copolymer. These are preferably polymers comprising two or more chemically distinct zones or segments (referred to as "blocks ") joined in a linear fashion, i.e. polymers which are polymerized rather than pendant or grafted, such as ethylene- or propylene- Lt; RTI ID = 0.0 > chemically < / RTI >

The olefin block copolymer (OBC) means an ethylene /? - olefin multiblock copolymer or a propylene /? - olefin multiblock copolymer. Wherein the olefin block copolymer comprises ethylene or propylene in the form of polymerizing at least one copolymerizable alpha -olefin comonomer and having a plurality of blocks or segments of two or more polymerized monomer units differing in chemical or physical properties, Chain.

In some embodiments, the multi-block copolymer may be represented by the following formula:

(AB) n

N is an integer greater than or equal to 1, preferably greater than 1, such as 2, 3, 4, 5, 10, 15, 20, 30, 40, 50, 60, 70, 80, 90, 100, ; "A" represents a hard block or segment; "B" represents a soft block or segment. Preferably, A and B are connected in a linear manner, not in a branched or star manner. "Rigid" segment refers to a block of polymerized units in which ethylene or propylene is present in amounts of at least 95 weight percent in some embodiments, and at least 98 weight percent in other embodiments. That is, the comonomer content in the hard segment is less than or equal to 5 wt%, in other embodiments less than or equal to 2 wt% of the total weight of the hard segment in some embodiments. In some embodiments, the hard segments are all or substantially all comprised of ethylene or propylene. On the other hand, a "soft" segment is a segment of polymerized units in which the comonomer content is greater than or equal to 5 wt%, in various embodiments greater than or equal to 8 wt%, greater than or equal to 10 wt%, or greater than or equal to 15 wt% of the total weight of the soft segments in some embodiments Block. In some embodiments, the comonomer content in the soft segment is at least 20 wt%, at least 25 wt%, at least 30 wt%, at least 35 wt%, at least 40 wt%, at least 45 wt%, at least 50 wt% Or more, or 60 wt% or more.

In one embodiment, the olefin block copolymer may have a density of 0.85 to 0.91 g / cc, or 0.86 to 0.88 g / cc.

In one embodiment, the olefin block copolymer has a melt index (MI) of from 0.01 to 30 g / 10 min, or from 0.01 to 20 g / 10 min as measured by ASTM D1238 (190 占 폚, 2.16 kg) 10 g / 10 min, or 0.1 to 5.0 g / 10 min, or 0.1 to 1.0 g / 10 min, or 0.3 to 0.6 g / 10 min.

In one embodiment, the olefin block copolymer may have a polydispersity index (PDI) of 1.7 to 3.5, or 1.8 to 3, or 1.8 to 2.5, or 1.8 to 2.2, when prepared in a continuous process. In production by batch or semi-batch process, the olefin block copolymer may have a PDI of 1.0 to 3.5, or 1.3 to 3, or 1.4 to 2.5, or 1.4 to 2.

In one embodiment, the olefin block copolymer may contain from 5 to 30 weight percent, or from 10 to 25 weight percent, or from 11 to 20 weight percent hard segment. The hard segment may contain from 0.0 to 0.9 mole percent of monomers derived from comonomers. The olefin block copolymer may also contain from 70 to 95 weight percent, or from 75 to 90 weight percent, or from 80 to 89 weight percent of the soft segment. The soft segment may contain less than 15 mole percent, or 9 to 14.9 mole percent, units derived from comonomers. In one embodiment, the comonomer may be butene or octene.

Since the olefin block copolymer has a chain structure in which blocks of a hard segment and soft segments are alternately connected, the olefin block copolymer has characteristics of combining rigidity of a hard segment and softness of a soft segment. Thus, it has higher heat resistance than the ethylene random copolymer having similar hardness, and the elastic recovery property can have a performance equal to or higher than that of the styrene-based or vulcanized olefin-based thermoplastic elastomer. In addition, it is economically more cost-effective than a styrene-based elastomer mixture without causing dust and environmental problems.

The olefin /? - olefin copolymer used in the elastic filler for artificial turf is preferably an olefin random copolymer (ORC) in that the value is preferably very low.

The olefin random copolymer may be a randomly polymerized form of ethylene or propylene and at least one copolymerizable? -Olefin comonomer.

When the ORC is a copolymer of ethylene and an? -Olefin, that is, an EAO, it may contain at least one copolymer of, for example, a C3-C20? -Olefin, a C3-C12? -Olefin or a C3-C8? -Olefin. Suitable alpha-olefins can be linear or branched (e.g., one or more C1-C3 alkyl branched chain or aryl groups). Specific examples are propene, butene, 3-methyl-1-butene, 3,3-dimethyl-1-butene, pentene, pentene having at least one methyl, ethyl or propyl substituent, hexene having at least one methyl, ethyl or propyl substituent Heptene having at least one methyl, ethyl or propyl substituent, octene having at least one methyl, ethyl or propyl substituent, nonenes having at least one methyl, ethyl or propyl substituent, ethyl, methyl or dimethyl substituted decene, . Particularly desired alpha-olefin comonomers are propylene, butene (e.g. 1-butene), hexene and octene (e.g. 1-octene or 2-octene). The ethylene content of such copolymers may be from about 60 mole percent to about 99.5 mole percent, in some embodiments from about 80 mole percent to about 99 mole percent, and in some embodiments from about 85 mole percent to about 98 mole percent. Likewise, the alpha-olefin content may range from about 0.5 mole percent to about 40 mole percent, in some embodiments from about 1 mole percent to about 20 mole percent, and in some embodiments from about 2 mole percent to about 15 mole percent. The distribution of the -olefin comonomers is typically random and uniform over different molecular weight fractions forming the ethylene copolymer.

When the ORC is a copolymer of propylene and an alpha -olefin, i.e., PAO, it may contain at least one copolymer of, for example, a C2-C20 alpha-olefin, a C2-C12 alpha-olefin, or a C2-C8 alpha-olefin. Suitable alpha-olefins can be linear or branched (e.g., one or more C1-C3 alkyl branched chain or aryl groups). Specific examples are ethylene, butene, 3-methyl-1-butene, 3,3-dimethyl-1-butene, pentene, pentene having at least one methyl, ethyl or propyl substituent, hexene having at least one methyl, Heptene having at least one methyl, ethyl or propyl substituent, octene having at least one methyl, ethyl or propyl substituent, nonenes having at least one methyl, ethyl or propyl substituent, ethyl, methyl or dimethyl substituted decene, . Especially desirable alpha-olefin comonomers are ethylene, butene (e.g., 1-butene), hexene and octene (e.g., 1-octene or 2-octene). The propylene content of such copolymers may be from about 60 mol% to about 99.5 mol%, in some embodiments from about 80 mol% to about 99 mol%, and in some embodiments from about 85 mol% to about 98 mol%. Likewise, the alpha-olefin content may range from about 0.5 mole percent to about 40 mole percent, in some embodiments from about 1 mole percent to about 20 mole percent, and in some embodiments from about 2 mole percent to about 15 mole percent. The distribution of the -olefin comonomers is typically random and uniform over different molecular weight fractions forming the propylene copolymer.

The density of the ethylene /? - olefin copolymer (EAO) or propylene /? - olefin copolymer (PAO) may be a function of the length and amount of? -Olefins. That is, the longer the length of the -olefin and the larger the amount of the -olefin, the lower the density of the copolymer. Generally speaking, the higher the density of the copolymer, the better retain the three-dimensional structure and the lower the density of the copolymer, the better the elastomeric properties can be.

The ORC is selected to have a density of from 0.86 to 0.90 g / cc, in some embodiments from about 0.861 to about 0.89 g / cc, and in some embodiments from about 0.862 to about 0.88 g / cc.

The silane coupling agent is present in the elastomer composition, grafting the olefin copolymer with a radical initiator contained in the composition, and allowing the crosslinking reaction to proceed in the presence of water. The elastic filler prepared by pelletizing the composition due to the silane coupling agent mixed in the elastomer composition may be crosslinked by heating in water. Further, when the composition is pelletized and then the elastic filler is applied as it is, moisture in the atmosphere is retained and natural crosslinking may occur over time.

The silane coupling agent is chemically bonded to the base resin to form a silane graft copolymer, and functions as a functional group for crosslinking the pelletized elastic filler. The silane coupling agent may have the form of an alkoxysilane compound. Examples of the alkoxysilane compound include vinyltrimethoxysilane, vinyltriethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, methyltriethoxysilane, methyltrimethoxysilane, methyltri (2-methoxy 3-methacryloyloxypropyl-trimethoxysilane, 3-mercaptopropyl-trimethoxysilane, 3-aminopropyl-triethoxysilane, 3-aminopropyl-trimethoxysilane, 3-glycidyloxypropyl-trimethoxysilane and the like can be used. These silane coupling agents may be used alone or in combination of two or more.

The degree of crosslinking can be controlled by the content of the amount of the silane coupling agent in the elastomer composition.

In the elastic filler for artificial turf of the present invention, the content of the silane coupling agent is 0.5 to 5 parts by weight, preferably 0.8 to 3 parts by weight, more preferably 1 to 2 parts by weight, based on 100 parts by weight of the base resin . If the content of the silane coupling agent is less than the above range, the effect of crosslinking is small and the heat resistance is insufficient, so that aggregation of the elastic fillers may occur at a high temperature in the summer. When the content exceeds the above range, the crosslinking density does not rise to some extent, .

To constitute the silane graft copolymer, the elastomer composition may contain a radical polymerization initiator. The radical polymerization initiator chemically grafts the base resin and the silane coupling agent, wherein the radical polymerization initiator is at least one selected from the group consisting of t-butyl cumyl peroxide, benzoyl peroxide, cumene hydroperoxide, dicumyl peroxide, t -Butyl peroxybenzoate, t-butyl peroxy isopropyl carbonate, t-butyl peroxylaurate, t-butyl peroxyacetate, di-t-butyl peroxyphthalate, t- , T-butyl hydroperoxide, t-butyl hydroperoxide, 1,3-bis (t-butylperoxyisopropyl) benzene, methyl ethyl ketone peroxide, 2,5- 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, di-t-butyl peroxide, 2,5- Butylperoxy) -3-hexane, n-butyl-4,4-bis (t-butylperoxy) valerate, Peel or benzene may be used and a mixture thereof.

If necessary, a catalyst may be further added to the elastomer composition in order to shorten the number of times in the grafting step. Examples of the catalyst used herein include dibutyl tin dilaurate, dibutyl tin dimaleate, dibutyl tin diacetate, dibutyl tin dilaurate, dioctyl tin maleate, dibutyl tin diacetate, dibutyl tin dioctoate, tetrabutyl Titanate, hexylamine, dibutylamine acetic acid, ferric tin, ferric tin octoate, lead naphthenate, zinc caprylate, cobalt naphthenate, and the like.

The catalyst may be contained in an amount of 0.05 to 1 part by weight, preferably 0.1 to 0.7 part by weight based on 100 parts by weight of the base resin. When the content of the catalyst is less than the above range, the crosslinking rate is low and a lot of energy and time are required. When the amount of the catalyst is less than the above range, the crosslinking rate may not be further accelerated.

The inorganic filler is added to the artificial turf to increase the specific gravity of the filler after the synthetic filler for artificial turf is applied to the artificial turf so as not to be washed away and to prevent thermal deformation. As the inorganic filler, calcium carbonate (CaCO ₃ ), talc, mica, clay, silica (SiO ₂ ), barium sulfate (BaSO ₄ ), magnesium carbonate (MgCO ₃ ) But calcium carbonate is most preferred from the viewpoint of cost. The inorganic filler may be used in an amount of 50 to 500 parts by weight, preferably 80 to 400 parts by weight, based on 100 parts by weight of the base resin. If the amount of the inorganic filler is less than 50 parts by weight, the specific gravity of the elastic filler for artificial turf may be lowered and may be lost by rainwater or the like. If the inorganic filler is more than 500 parts by weight, the hardness may be excessively increased and elasticity may be lost, It can be easily broken due to sliding during a game.

The base resin used in the elastic filler for artificial turf according to an embodiment of the present invention may include natural rubber, synthetic rubber, or a combination thereof in order to complement the performance of the olefin copolymer or to reduce the cost thereof May be further included.

The natural rubber may be a general natural rubber or a modified natural rubber. The above-mentioned general natural rubber may be used as long as it is known as natural rubber, and the country of origin and the like are not limited. The natural rubber includes cis-1,4-polyisoprene as a main component, but may also include trans-1,4-polyisoprene depending on required characteristics. Therefore, in addition to natural rubber containing cis-1,4-polyisoprene as a main component, natural rubber including trans-1,4-isoprene as a main component, such as balata, Rubber may also be included. The modified natural rubber means that the general natural rubber is modified or purified. Examples of the modified natural rubber include epoxidized natural rubber (ENR), deproteinized natural rubber (DPNR), hydrogenated natural rubber and the like.

The synthetic rubber may be at least one selected from the group consisting of styrene butadiene rubber (SBR), modified styrene butadiene rubber, butadiene rubber (BR), modified butadiene rubber, chlorosulfonated polyethylene rubber, epichlorohydrin rubber, fluorine rubber, silicone rubber, (NBR), modified nitrile butadiene rubber, chlorinated polyethylene rubber, styrene butadiene styrene rubber (SBS), styrene ethylene butylene styrene (SEBS) rubber, styrene isoprene styrene rubber (SIS), ethylene propylene rubber, ethylene propylene (EPDM) rubber, hyaluron rubber, chloroprene rubber, ethylene vinyl acetate rubber, acrylic rubber, hydrin rubber, vinyl benzyl chloride styrene butadiene rubber, bromomethyl styrene butyl rubber, maleic styrene butadiene rubber, carboxylic styrene butadiene rubber , Epoxy isoprene rubber, maleic acid (BIMS), a vulcanized olefinic thermoplastic elastomer, and combinations thereof. The thermoplastic elastomer composition according to claim 1, wherein the thermoplastic elastomer is selected from the group consisting of polybutylene terephthalate, Lt; / RTI >

Preferably, the rubber may be a styrene-based thermoplastic elastomer or a vulcanized olefin-based elastomer. When the styrenic thermoplastic elastomer is mixed with the base resin, the elastic recovery rate of the elastic filler for artificial turf according to an embodiment of the present invention can be improved. On the other hand, when the vulcanized olefin-based elastomer is mixed with the base resin, the heat-resisting property of the elastic filler for artificial turf according to one embodiment of the present invention can be improved.

Also, in some embodiments, the base resin may be a mixture of ORC, OBC, and rubber in appropriate proportions in consideration of extrusion workability, heat resistance, elastic recovery, and the like. The rubber is preferably used in an amount of 5 to 50 parts by weight based on 100 parts by weight of the olefin copolymer in consideration of economy and performance.

The elastic composition may further comprise a processing aid. The polybutene or process oil which can be used as processing aid can improve the processability of the mixed compound and can provide flexibility by preventing increase in hardness due to the addition of a large amount of inorganic filler. The processing aid may be added in an amount of 2 to 500 parts by weight, preferably 10 to 200 parts by weight based on 100 parts by weight of the base resin. If the content is less than the above-mentioned range, the flowability during processing may be lowered. If the content is higher than the above range, bleeding may occur.

Polybutene is excellent in compatibility with olefin resins, and is free from migration due to low molecular weight, and is free from bleeding in water, and is environmentally friendly. The molecular weight of the polybutene used is preferably about 300 to 8,000. Mineral oils such as paraffin type or naphthenic type may be used as the process oil.

The elastic composition may further include a resin stabilizer for the purpose of changing physical properties of the elastic body and preventing color discoloration after the application. The resin stabilizer may include a heat stabilizer, an antioxidant, a UV stabilizer, etc., and may be used in the range of 0.01 to 10 parts by weight based on 100 parts by weight of the base resin. When the amount of the resin stabilizer is less than 0.01 part by weight, the effect is small. When the amount of the resin stabilizer is more than 10 parts by weight, economical efficiency may be deteriorated.

As the heat stabilizer, there may be used tin-based, lead-based, cadmium-based, zinc-based, and preferably low-toxicity zinc-based materials. Examples of the antioxidant include amine, phenol, phosphorus, Benzophenone, benzotriazole, and hindered amine may be used.

The elastic composition may further comprise a pigment. In the case of a black tire having a waste tire rubber chip, it can absorb sunlight well and cause a rise in temperature. Therefore, when a pigment is used, an elastic filler with various colors can be manufactured by being out of black. For example, the elastomer composition may further comprise an index of green pigment such as artificial turf. The amount of the pigment is preferably 0.1 to 4 parts by weight based on 100 parts by weight of the base resin in consideration of efficiency.

The elastic filler for artificial turf has a rebound resilience of 50% or more, usually 50 to 60% when tested by ASTM D-2632. In artificial turf, when the rebound resilience of the elastic filler is less than 50%, there is a problem that the repulsive force of the soccer ball is below the reference, and when the rebound resilience is more than 60%, the athlete is injured Or you can feel fatigue easily.

The synthetic filler for artificial turf has a permanent compression set of 2 to 20%, or 5 to 15% at room temperature based on ASTM D-395. The permanent compression ratio at 70 캜 is 15 to 40% or 20 to 35%. Since the synthetic filler for artificial turf has an excellent compression set ratio, the elastic filler can maintain its original shape for a long period of time and does not cause clumping at high temperatures in the summer.

The elastic filler for artificial turf according to an embodiment of the present invention can greatly improve the heat resistance by crosslinking the olefin copolymer. It is economical to produce a high quality artificial turf filler by using an olefin random copolymer which is inexpensive but has a low heat resistance as a base resin. Generally, in case of artificial turf applied to a playground, there is a phenomenon that due to high temperature in summer (there is a research report that it goes up to 70 ° C), the filler material softens or melts so that they stick together and become sticky. This problem can be solved by using the elastic filler for artificial turf according to the embodiment.

According to one embodiment, the elastic composition may be extruded and pelletized to produce an elastic filler for artificial turf.

The elastic filler for artificial turf according to an embodiment of the present invention can be produced by the following manufacturing method. First, an elastic composition comprising a silane coupling agent in a mixture of a base resin containing an olefin copolymer and an inorganic filler is provided. The elastic composition may further contain at least one member selected from the group consisting of an initiator, a catalyst, a processing aid, a resin stabilizer and a pigment.

Next, the elastic composition is kneaded. A kneader such as an open roll or a kneader mixer may be used for kneading the respective components. For example, kneading is carried out at a temperature of 130 to 160 ° C and the kneaded product is discharged at a temperature of 140 to 170 ° C.

The kneaded elastomer composition is then extruded and pelletized to obtain an elastic filler. For extrusion of the above-mentioned elastic composition, a general extrusion apparatus such as a Banbury kneader, a Buss kneader, a single screw extruder, a twin screw extruder and the like can be used. The extrusion step may be performed at a temperature range of, for example, 90 to 170 캜. In the extrusion process, a silane coupling agent may be chemically bonded to the base resin to form a silane graft copolymer.

When the elastic composition is put into an extruder and extruded at a high temperature, a die capable of adjusting the size of the extruder in the range of 0.5 to 3 mm is installed in the compression head of the extruder, and hot cutting or underwater cutting ) Method, an elliptic or circular pellet-shaped chip having an average size of 0.5 to 3 mm can be manufactured.

In a preferred embodiment, the pelletized elastic filler may be heated to elevate the temperature in water. For example, the water-repellent step may be carried out by immersing the pelletized elastic filler in water at 70 to 90 ° C, followed by crosslinking for 3 to 5 hours.

In a preferred embodiment, the pelletized elastic filler may be placed in a natural state to allow hydration. At this time, the silane coupling agent reacts with water in the atmosphere and the crosslinking can proceed slowly.

The above-mentioned elastic filler for artificial turf is not a pulverized chip like a waste tire but a pellet formed by extruding into a uniform particle size. Therefore, it does not generate dust, has excellent heat resistance and elasticity, is harmless to the human body, Do not. Also, it is more economical because it is cheap.

The techniques disclosed herein are more specifically described by the following examples. However, the scope of the disclosed technology is not limited to the following embodiments, and various applications of the embodiments are possible within the technical scope from the matters described in the claims.

<Examples>

Waste Tire Chip : CTCR 01 (1.0-3.0 mm) of CRIOTECH CO., LTD.: The thread portion of the waste tire was peeled off and the chip was manufactured by freezing and pulverizing at minus 200 ° C.

Comparative Examples 1 to 4 : The entire composition was put into a Kneader at 120 ° C and mixed. The kneaded composition was discharged at 150 ° C and then transferred to a hopper of a twin-screw extruder, followed by underwater cutting of an extruder controlled at 160 ° C (Underwater Cutting) An artificial turf elastic filler was prepared by pelletizing a rotating knife attached to the dice at a rotation speed of 150 rpm to a diameter of 2 mm. The elastic filler was placed in a mold having a thickness of 10 mm, heated at 150 ° C. for 5 minutes, cooled to room temperature, and the rebound resilience and the permanent compressive strain rate were measured.

EXAMPLES 1 to 7 : The entire composition was put into a Kneader at 120 ° C. and mixed. The kneaded composition was discharged at 150 ° C. and then transferred to a hopper of a twin-screw extruder, followed by underwater cutting of an extruder controlled at 160 ° C. (Underwater Cutting) A rotating knife attached to a dice was pelletized to a diameter of 2 mm while rotating at 150 rpm to produce an unexchanged artificial turf elastic filler. The elastic filler was placed in a mold having a thickness of 10 mm, heated at 150 ° C. for 5 minutes and then cooled to room temperature. The rebound resilience and the permanent compressive strain rate were measured after watering at 60 ° C. for 24 hours.

As the base resin and silane coupling agent, the following were used.

EVA-1: Ethylene Vinyl Acetate Copolymer (Hanwha EVA 1833 (Hanwha Chemical, VA: 33%, MI: 13, hardness: 63)

EAO-1: Ethylene Alpha Olefin Copolymer: Engage 8180 (Dow Chemical, density: 0.863, MI: 0.5, hardness: 63)

Olefin Block Copolymer: Infuse D9507 (Dow Chemical, density: 0.877, MI: 5.0, hardness: 60)

SEBS-1: Styrene Ethylene Butylene Styrene (Tuftec H1052, Asahi Kasei, density: 0.89, MI: 3.0, hardness: 67)

Silane-1: Vinyltrimethoxysilane

Table 1 shows the results of physical properties of the elastic fillers for artificial turf of Comparative Examples and Examples.

[Table 1]

- Repulsive elasticity: tested by ASTM D-2632, 50% or more is good and less than 50% is poor.

- Permanent Compression Ratio: As determined by ASTM D-395, at room temperature permanent compressive strain less than 25% is good, more than 25% is poor, 70 ℃ permanent compressive strain less than 40% is good, and more than 40% is poor .

- High temperature stacking test: 1,000 g of sample is placed in a 20 cm wide nylon cloth envelope of 20 cm width and 20 cm length, placed in an oven at 70 ° C., and a stainless steel plate (weight 1,000 g) having a diameter of 15 cm and a thickness of 7 mm is placed thereon After heating for 24 hours, it was taken out, and the weight of the particles gathered among the filler particles in the nylon envelope was judged as being good, less than 30 g being defective, more than 30 g being defective and more than 900 g being extremely defective.

- Dust test: The prepared filler samples were applied to artificial turf of 1 mx 1 m, and then the soccer ball was dropped at a height of 1 m to visually observe the extent of dust generation.

As can be seen from the above Table 1, the synthetic filler for artificial grass of the embodiment prepared by melt-kneading the ethylene copolymer disclosed in this specification had a compression set at a high temperature of 60 %, Which indicates that the elasticity recovery rate is excellent, and the price is lower than that of the synthetic filler for artificial turf made by SEBS of Comparative Example 3. [ In addition, by the high temperature load - accumulation test, the accumulation of filler particles is small even at a temperature of 70 ° C, and the heat resistance is suitable for artificial turf.

Also, in case of waste tire chips, there is a problem that the surface temperature is raised to 70 ° C when continuous sunlight is received at the ambient atmosphere temperature of 30 ° C, Elastic fillers for artificial turf do not have such problems and can provide a comfortable exercise environment for the players.

Claims (17)

(CaCO ₃ ), talc, mica, clay, silica (SiO ₂ ), barium sulphate (BaSO ₄ ) and magnesium carbonate (MgCO ₃ ) are mixed with a base resin containing an olefin copolymer. And a silane coupling agent is pelletized into a mixture of at least one inorganic filler selected from the group consisting of a silane coupling agent,
Wherein the silane coupling agent is present in a mixed state with the mixture or is grafted to the olefin copolymer so that the olefin copolymer is in the form of water. The method according to claim 1,
Wherein the olefin copolymer is selected from the group consisting of i) ethylene, and ii) a C3-C10 alpha monoolefin, a C1-C12 alkyl ester of a C3-C20 monocarboxylic acid, an unsaturated C3-C20 mono- or dicarboxylic acid, an anhydride of an unsaturated C4-C8 dicarboxylic acid, And a vinyl ester of a C2-C18 carboxylic acid. The synthetic filler for artificial turf is a copolymer of one or more ethylenically unsaturated monomers selected from the group consisting of vinyl esters of C2-C18 carboxylic acids. The method according to claim 1,
Wherein the olefin copolymer is an olefin /? - olefin copolymer (OAO). The method of claim 3,
Wherein the olefin is ethylene or propylene, and the? -Olefin is an olefin having 3 or more carbon atoms having a double bond at the terminal. The method of claim 3,
Wherein said olefin /? - olefin copolymer is an olefin random copolymer. 6. The method of claim 5,
Wherein the olefin random copolymer has a form in which ethylene or propylene and at least one copolymerized? -Olefin comonomer are randomly polymerized. The method of claim 3,
The olefin /? - olefin copolymer is an olefin block copolymer, which is an elastic filler for artificial turf. 8. The method of claim 7,
Wherein the olefin block copolymer comprises ethylene and at least one copolymerizable alpha -olefin comonomer in polymerized form and is a multiblock copolymer having a plurality of blocks or segments of two or more polymerized monomer units differing in chemical or physical properties Elastic filler for turf. The method according to claim 1,
Wherein the base resin further comprises at least one rubber selected from the group consisting of natural rubber, synthetic rubber, and combinations thereof. 10. The method of claim 9,
Wherein the content of the rubber is 5 to 50 parts by weight based on 100 parts by weight of the olefin copolymer. The method according to claim 1,
Wherein the silane coupling agent is an alkoxysilane compound. The method according to claim 1,
Wherein the content of the silane coupling agent is 0.5 to 20 parts by weight based on 100 parts by weight of the base resin. The method according to claim 1,
An elastic filler for artificial turf based on ASTM D-395 having a permanent compression set of 2 to 20% at room temperature and a permanent compression ratio of 15 to 40% at 70 캜. delete Providing an elastomer composition comprising a silane coupling agent in a mixture of an inorganic filler and a base resin containing an olefin copolymer;
Kneading the elastomer composition;
Extruding and pelletizing the kneaded elastomer composition to obtain an elastic filler; And
And elevating the pelletized elastic filler by heating in water to make water soluble. Providing an elastomer composition comprising a silane coupling agent in a mixture of an inorganic filler and a base resin containing an olefin copolymer;
Kneading the elastomer composition;
Extruding and pelletizing the kneaded elastomer composition to obtain an elastic filler; And
Wherein the pelletized elastic filler is placed in a natural state to allow water to flow therethrough. delete